title: Linear phase-error correction for improved water and fat separation in dual-echo dixon techniques.
abstract: Large and spatially-linear phase errors along the frequency-encode direction may be induced by several common and hard-to-avoid system imperfections such as eddy currents. For data acquired in dual-echo Dixon techniques, the linear phase error can be more aggravated when compared to that acquired in a single echo and can pose challenges to a phase-correction algorithm necessary for successful Dixon processing. In this work, we propose a two-step process that first corrects the linear component of the phase errors with a modified Ahn-Cho algorithm (Ahn CB and Cho ZH, IEEE Trans. Med. Imaging 6:32, 1987) and then corrects the residual phase errors with a previously-developed region-growing algorithm (Ma J, Magn. Res. Med. 52:415, 2004). We demonstrate that successive application of the two-step process to data from a dual-echo Dixon technique provides a "1-2 punch" to the overall phase errors and can overcome local water and fat separation failures that are observed when the region-growing-based algorithm is applied alone.
authors.affiliation: Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA. jma@di.mdacc.tmc.edu
authors.forename: Jingfei
authors.initials: J
authors.lastname: Ma
authors.forename: Zachary
authors.initials: Z
authors.lastname: Slavens
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.forename: Ersin
authors.initials: E
authors.lastname: Bayram
authors.forename: Lloyd
authors.initials: L
authors.lastname: Estowski
authors.forename: Ken-Pin
authors.initials: KP
authors.lastname: Hwang
authors.forename: James
authors.initials: J
authors.lastname: Akao
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Vu
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000378:metabolism*; D016477:Artifacts; D001834:Body Water / Q000378:metabolism*; D003198:Computer Simulation; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D007089:Image Enhancement / Q000379:methods*; D016014:Linear Models; D009682:Magnetic Resonance Spectroscopy; D013382:Subtraction Technique